JP2982846B2 - Method for producing monoalkenylbenzenes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing monoalkenylbenzenes by alkenylating an aromatic hydrocarbon compound with a conjugated diene having 4 or 5 carbon atoms. Monoalkenylbenzenes are useful as intermediate materials for various organic compounds such as high-molecular monomers and pharmaceuticals, for example, 5- (o-tolyl) -2 produced from o-xylene and 1,3-butadiene. -Pentene can be converted to industrially useful 2,6-naphthalenedicarboxylic acid by ring closure, dehydrogenation, isomerization and oxidation.

[0002]

2. Description of the Related Art An aromatic hydrocarbon compound having 4 or 5 carbon atoms is used.
As a catalyst for producing monoalkenylbenzenes by alkenylation of side chains using conjugated dienes of the above, a method using an alkali metal such as sodium or potassium and an alloy thereof is known. For example, German Patent 5575
No. 14 describes a method using sodium metal as a catalyst, which is described in Eberhardt et al., J. Org. Chem., Vol. 30 (1965),
pp82-84 describes a method of using sodium metal supported on an alkaline earth metal oxide. Japanese Patent Publication No. 50-17797 describes a method using metal potassium.
No. -8930 describes a method using a potassium-sodium alloy or a mixture of metallic potassium and metallic sodium. Also, U.S. Pat. No. 3,244,758 and the above-mentioned J. Org. Chem., Vol. 30 (1965), pp. 82-84 describe a method of using potassium metal supported on an alkali metal oxide or an alkaline earth metal oxide. ing. Further, JP-A-47-27929 and JP-A-47-31935 disclose a potassium compound and metallic sodium at 300 ° C or 3 ° C.
A method is disclosed in which a mixture obtained by heat treatment at a temperature of 50 ° C. or higher is used as a catalyst.

[0003]

SUMMARY OF THE INVENTION Among the above known methods,
When the metal sodium is used as it is or supported on an alkaline earth metal oxide and used as a catalyst, the activity and the selectivity are not sufficient and are not practical. In addition, a method using a metal potassium catalyst, a potassium-sodium alloy or a mixture of metal potassium and metal sodium as a catalyst has a high activity as a catalyst, but a large amount of ignitable metal is required for industrial use. There is a problem in terms of safety due to use, and there is also a problem in terms of economy because a large amount of expensive metallic potassium is used. On the other hand, a method using a mixture obtained by heat-treating a metal sodium and a potassium compound at a high temperature as a catalyst has the feature that potassium metal or a potassium alloy is not used directly, but has insufficient activity, and also has a flammable powder. This is not always a practical method, such as the need to treat the body at high temperatures. In addition, in the case of these alkali metal plain metals, alloys, or the above-mentioned supported catalysts, elution of the alkali metal component into the reaction product solution is remarkably observed, which makes it difficult to maintain the catalytic activity for a long period of time. It is one of the major causes. Further, the alkali metal component eluted into the reaction product solution also has a problem in that the monoalkenyl benzenes are separated and purified from the reaction product solution by distillation, such as a problem of deterioration of the monoalkenyl benzenes and a problem of clogging of the distillation column. Will cause. In view of the above, an object of the present invention is to provide a method for alkenylating a side chain of an aromatic hydrocarbon compound using a conjugated diene having 4 or 5 carbon atoms.
It is an object of the present invention to provide a method for stably producing monoalkenylbenzenes over a long period of time at a high yield, at a low cost, and more safely.

[0004]

Means for Solving the Problems The present inventors have developed an excellent method for producing monoalkenylbenzenes by alkenylating the α-position of an aromatic hydrocarbon compound with a conjugated diene having 4 or 5 carbon atoms. As a result of intensive investigations for the purpose of developing a method, a mixture obtained by calcining a carbon material and a potassium compound is heated under an inert gas to a composition obtained by heat-treating metallic sodium at or above its melting point as a catalyst. It has been found that monoalkenyl benzenes can be stably produced over a long period of time by a method with high yield, low cost and high safety by using the same, and the present invention has been completed.

The catalyst prepared by the method of the present invention has a high activity in the side chain alkenylation reaction of an aromatic hydrocarbon compound with a conjugated diene, and has a high yield and a high selectivity even with a small amount of catalyst. Alkenylbenzenes were obtained.
Further, the ignitability of the alkali metal was significantly reduced, and the handling of the catalyst became easy. Furthermore, the present catalyst has been found to maintain a high activity stably over a long period as the most significant feature. In addition, the elution of the alkali metal component from the catalyst into the reaction product solution is extremely small, and there is no problem such as deterioration of the produced monoalkenylbenzenes during purification and clogging of the distillation column. It has been found that benzenes can be produced. That is, the present invention relates to monoalkenylbenzenes obtained by alkenylating a side chain of an aromatic hydrocarbon compound having one or more hydrogen atoms bonded to the α-position of the side chain using a conjugated diene having 4 or 5 carbon atoms. In producing, to a mixture obtained by calcining a carbon material and a potassium compound at 300 ° C to 700 ° C, under an inert gas, add metallic sodium,
A composition obtained by heat treatment at 100 ° C. to 400 ° C. is used as a catalyst. Hereinafter, the present invention will be described in detail.

The aromatic hydrocarbon compound having one or more hydrogen atoms bonded to the α-position of the side chain used in the present invention includes:
The following compounds are used. Monocyclic aromatic hydrocarbons include monoalkylbenzenes such as toluene, ethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, sec-butylbenzene, isobutylbenzene, o-, m- and p-xylene, o -, M- and p-ethyltoluene, o-, dialkylbenzenes such as m- and p-diethylbenzene, mesitylene, trialkylbenzenes such as pseudocumene, 1,2,3,5-tetramethylbenzene, 1,2, Polyalkylbenzenes such as 4,5-tetramethylbenzene, pentamethylbenzene, hexamethylbenzene and the like are used.
-And 2-methylnaphthalene, dimethylnaphthalenes,
Alkyl tetrahydronaphthalenes, alkyl indans and the like are used. In the present invention, the conjugated diene having 4 or 5 carbon atoms as one raw material is 1,3-butadiene,
1,3-pentadiene and isoprene.

The carbon material used in the catalyst of the present invention includes graphite and amorphous carbon. As graphite, natural graphite, quiche graphite, pyrolytic graphite, artificial graphite, expanded graphite and the like are used. The amorphous carbon is not particularly limited, such as non-graphitizable carbon, easily graphitizable carbon, etc., and the raw material is petroleum-based, coal-based, natural plant-based, and synthetic polymer-based starting material, such as calcined starting material. Absent. For example, fired petroleum pitch or coal pitch, coconut charcoal, PAN carbon fiber,
Glassy carbon, carbon black, activated carbon and the like.
In addition, sulfur, nitrogen, oxygen,
There is no particular limitation as long as it does not affect the reaction even if it contains elements other than carbon such as iron and nickel. As the carbon material of the present invention, any of the above materials can be used, but those obtained by calcining petroleum-based pitch and PAN-based pitch are particularly preferable in that they provide stable reaction results over a long period of time. .

[0008] In producing monoalkenylbenzene, in order for the catalyst to exhibit a predetermined performance, it is necessary to use α in the side chain as a raw material.
It is necessary that the catalyst does not dissolve and float in the aromatic hydrocarbon compound having one or more hydrogen atoms bonded at each position and the product monoalkenylbenzenes. Since the catalyst according to the present invention uses a carrier in which a carbon material is calcined in advance with a potassium compound at 300 ° C. or higher, even if a carbon material having a low carbonization degree is used, it becomes insoluble and non-floating. Therefore, the degree of carbonization and the true density of the carbon material that is the starting material of the catalyst are not particularly limited. The surface area is not particularly limited, and is 0.1 m ² / g close to that of graphite.
2000m ² / close to high surface area activated carbon from (SBET)
There is no problem even if g (SBET) is in a wide range. As the surface spacing, d002 of graphite = 0.3354n
There is no particular limitation as long as it is at least m, and there is no problem even if the crystallite diameter is in a wide range from Lc = 200 nm for graphite to about 0.10 nm for carbon black.
The physical properties of the amorphous carbon used in the present invention are as follows:
It is not uniquely determined, but is determined as a result of selecting a suitable preparation method in consideration of the sintering temperature, sintering time, sintering atmosphere and the like according to the difference in starting materials, impurity concentrations, and the like.

Next, a method for preparing a catalyst by adding metallic sodium to a mixture obtained by calcining a carbon material and a potassium compound under an inert gas and heat-treating the mixture at a temperature equal to or higher than its melting point will be described. The catalyst is different from a conventionally used catalyst in which an alkali metal is supported on a metal oxide carrier. When the alkenylation reaction is carried out using the catalyst according to the present invention, the amount of the alkali metal component eluted into the reaction solution is greatly reduced as compared with the conventional one using a metal oxide carrier, and is stable over a long period of time. High activity can be maintained. In the catalyst, the potassium component occluded and / or adsorbed in the mixture during the heat treatment of the mixture obtained by calcining the carbon material and potassium with the metallic sodium is subjected to a metal exchange reaction with the metallic sodium to cause an alkenylation reaction. Converted to active metallic potassium. The amount of the alkali metal component eluted by the present catalyst is small because the potassium metal thus produced interacts with the surface functional groups of the carbon material, and the occlusion action between carbon material layers known as intercalation. This is because the holding force increases.

As a method for preparing a mixture of a carbon material and a potassium compound, any method can be used as long as it can mix and disperse both well, and either a wet method or a dry method can be adopted. Preparation is preferred.
Further, as the solvent used in the wet method, a solvent that sufficiently dissolves the potassium compound and has a high affinity for the carbon material, for example, a mixed solvent of a lower alcohol such as methanol, ethanol, and isopropyl alcohol and water is most preferable. At this time, for example, it is preferable to dissolve a potassium compound in a small amount of water, then mix and disperse the carbon material in a solution obtained by mixing ethanol, and then volatilize the solvent and dry the mixture. The mixing ratio of the carbon material and the potassium compound is 0.01 to 1 part by weight, preferably 0.1 to 0.5 part by weight, as potassium metal, based on 1 part by weight of the carbon material. When the mixing ratio of the potassium compound is smaller than this range, a side reaction of the alkenylbenzenes to be generated easily occurs, the catalytic activity tends to decrease, and a large amount of catalyst is required to maintain high activity. Inconveniences such as complicated processing after the reaction occur. On the other hand, when the mixing ratio of the potassium compound is large, it takes a long time to obtain a highly active catalyst, and it is necessary to calcine at a higher temperature. It is not preferable. The firing temperature is in the range of 300 ° C to 700 ° C,
The temperature is preferably from 400 ° C. to 600 ° C., and the firing atmosphere may be any of air and an inert gas such as nitrogen or argon. If the calcination temperature is higher than this range in an air atmosphere, the carbon material will burn and the desired mixture will not be obtained, and if it is lower than this range, sufficient catalytic activity will not be obtained. As the potassium compound used in the present invention, KOH, K ₂ C
O ₃ , K ₂ SO ₄ , potassium aluminate, potassium alcoholate, potassium phenolate, and potassium salts of organic acids are used, but KOH, K ₂ CO ₃ , K ₂ SO ₄ , and potassium alcoholate are preferred, and KOH, K ₂ CO
₃ is most preferred. These potassium compounds may contain other salts, such as nitrates and sulfates, up to an equimolar amount.

As described above, the mixture obtained by mixing and firing a carbon material and a potassium compound is mixed with metallic sodium.
The catalyst of the present invention is prepared by heat treatment under an inert gas. The inert gas referred to herein is a gas that does not substantially react with the catalyst prepared under the catalyst preparation conditions, and specifically includes nitrogen, helium, argon and the like. The heating temperature at this time is from the melting point of metallic sodium to 350 ° C. or less, preferably 100 to 300 ° C. If the heat treatment temperature is higher than 350 ° C., stable reaction results cannot be obtained for a long period of time. The time of the heat treatment is usually in the range of 5 minutes to 300 minutes. When potassium or the like is contained in metallic sodium, the sodium becomes liquid at a temperature lower than the melting point of metallic sodium. In this case, the catalyst can be sufficiently prepared as long as the temperature is higher than the temperature at which the sodium becomes liquid. If the metallic sodium does not melt, it is difficult to uniformly disperse and effectively contact the metallic sodium with the mixture prepared from the carbon material and the potassium compound, and it takes a long time to prepare the metallic sodium. Absent.

In using the composition obtained as described above in the reaction as the catalyst of the present invention, various reaction systems are employed. For example, a method in which raw materials are supplied to a reactor charged with a catalyst by a batch method or a semi-batch method, a method in which a catalyst and raw materials are continuously supplied to a reactor in a completely mixed flow method, or a method in which a catalyst is charged into a reactor and raw materials are charged A fixed bed distribution system or the like for distribution can be adopted. The reaction method should be appropriately selected depending on the kind of the desired reaction product, but generally, a method in which an aromatic hydrocarbon as one of the raw materials is present in excess with respect to the conjugated diene. And the selectivity to monoalkenylbenzenes can be improved. For that purpose, a method of continuously supplying the conjugated diene to the reaction system by a semi-batch method is preferable, and when the reaction is continuously performed by a complete mixing method or a fixed bed flow method, the reactor is preferably used. Is preferably divided into multiple stages and a reaction system capable of lowering the concentration of conjugated dienes in the reactor, such as supplying conjugated dienes to each stage, is preferable because a high selectivity can be obtained.

The reaction temperature in the method of the present invention is 50 to 50.
It is in the range of 300C, preferably 90-200C. When the reaction temperature is lower than this, the reaction occurs, but a sufficient reaction rate cannot be obtained, and the selectivity tends to deteriorate. If the temperature is higher than this, by-products such as tar are increased, which is not preferable. The reaction pressure is a pressure necessary for the starting aromatic hydrocarbon and the product to be substantially present as a liquid under the reaction conditions, and is 0.05 to 50 atm, preferably 0.1 to 20 atm in absolute pressure. Pressure range. In the method of the present invention, the ratio of the conjugated diene having 4 or 5 carbon atoms as one raw material to the raw aromatic hydrocarbon is generally 0.01 to 1, preferably 0.03 to 0.5 in a molar ratio. Range. If the amount of diene is larger than this, the produced monoalkenylbenzene further reacts with the diene to increase the production of a compound in which two or more molecules of diene are added to one molecule of aromatic hydrocarbon. This is not preferable because the rate becomes worse. The amount of the catalyst used in the method of the present invention is 0.0
It is at least 1%, preferably at least 0.05%.

In carrying out the method of the present invention, a reaction system such as a batch system, a semi-batch system, and a completely mixed circulation system is employed. 0.1 to 10 hours are employed. In the case of the fixed bed circulation system, the LSV of the aromatic hydrocarbon is usually 0.1 to 10 h ^-1 . In the case where the reaction is carried out by suspending the catalyst, separation of the reaction solution and the catalyst after the reaction can be easily performed by a general method such as sedimentation, centrifugation, or filtration. The separated catalyst may be circulated to the reaction system, or may be circulated to the catalyst preparation step after performing necessary treatment such as washing of the attached organic substance with an organic solvent or water.

[0015]

According to the method of the present invention, monoalkenyl benzenes which are industrially useful by using an aromatic hydrocarbon compound and a conjugated diene compound can be stably produced for a long time in a high yield, at a low cost and in a safer method. It can be manufactured as a product, and its industrial significance is great.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. EXAMPLE 1 Petroleum-based synthetic pitch (AR pitch manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as a carbon material under a nitrogen atmosphere in 80 ml of a water / ethanol (1/9 weight ratio) solution containing 8.34 g of potassium hydroxide as a potassium compound. 20.0 g heat-treated at ℃ for 3 hours was added, and the mixture was stirred and mixed at room temperature for 1 hour. The solvent was distilled off under reduced pressure, and 11
After drying at 5 ° C. overnight, it was further fired at 500 ° C. in air. 5.00 g of the mixed and calcined product was stirred at 200 ° C. in a nitrogen atmosphere, and 0.60 g of metallic Na was added thereto, followed by stirring at that temperature for 30 minutes. To the catalyst powder thus obtained, 1000 g of o-xylene dehydrated using a molecular sieve was added in a nitrogen stream, and heated to 140 ° C. While stirring under normal pressure,
70 g of 1,3-butadiene was introduced for 1 hour and reacted. After cooling the reaction solution and allowing the catalyst to settle, the upper layer reaction solution was taken out, a part of the reaction solution was taken, and analyzed by gas chromatography. Further, o-xylene 100
0 g was added and the same reaction was performed. Perform the above operations
The process was repeated until the yield of 5- (o-tolyl) -2-pentene was reduced to 95% of the initial value, and the number of the repetitions was defined as the number of reactions. The reaction results are shown in Table 1.

Examples 2 to 6 As shown in Table 1, the mixing ratio of petroleum synthetic pitch (AR pitch manufactured by Mitsubishi Gas Chemical) at 510 ° C. in a nitrogen atmosphere and potassium hydroxide was used. Firing atmosphere and firing temperature when preparing a carrier by firing the mixture of
A catalyst was prepared in the same manner as in Example 1 except that the amount of the composition thus obtained was changed.
The reaction was carried out in the same manner as described above. The results are shown in Table 1.

Example 7 A reaction was carried out in the same manner as in Example 1 except that potassium carbonate was used instead of potassium hydroxide as a potassium compound. The results are shown in Table 1. Examples 8 to 9 A catalyst was prepared in the same manner as in Example 1 except that a carbonaceous material obtained by changing the heat treatment temperature of petroleum-based synthetic pitch (AR pitch manufactured by Mitsubishi Gas Chemical) was used as a raw material. The reaction was performed similarly. The results are shown in Table 2.

Examples 10 to 12 As shown in Table 1, a PAN-based synthetic pitch was used as a carbon material in a nitrogen atmosphere in place of a petroleum-based synthetic pitch calcined product under a nitrogen atmosphere.
C. (Example 10), carbon graphite (Kanto Chemical Reagent, Example 11), and activated carbon (Kanto Chemical Reagent, Example 12) were used. A catalyst was prepared by the method, and the reaction was carried out in the same manner as in Example 1. The results are shown in Table 2.

[0020]Comparative Example 1 Heat and stir 0.6g of metallic sodium and 1.0g of metallic potassium
Performed using prepared sodium-potassium alloy as catalyst
The reaction was carried out as in Example 1. The results are shown in Table 3.Comparative Example 2 Use 20 g of alumina instead of 20 g of carbon material and KOH and aluminum
Set the firing temperature of the mixture with Lumina at 550 ° C and treat with Na
A method similar to that of Example 1 was performed except that the temperature was set to 150 ° C.
A catalyst was prepared and reacted in the same manner as in Example 1. The result
The results are shown in Table 3. Comparative Example 3 Potassium hydroxide petroleum synthetic pitch (AR pipe manufactured by Mitsubishi Gas Chemical)
Baking with heat treated at 510 ° C under nitrogen atmosphere
Heat treatment of mixture and metallic sodium at 400 ° C
A catalyst was prepared in the same manner as in Example 1 except that
The reaction was carried out as in 1. The results are shown in Table 3.

[0021]

[Table 1] 材料 Carbon material type K compound Calcination K compound treatment OTP^{* 3} Reaction Type Atmosphere-Carbon Temperature Yield Number Mixing Ratio Temperature Mixture Volume (° C) (%) (wt Ratio)^{* 1} (℃) (g)^{* 2} Na content (g) 実 施 Implementation MGC AR-Pitch KOH in air 5.0 200 71.7 17 Example 1 510 ℃ (0.20) 500 (0.6) under nitrogenHeat treated Implementation Same as above KOH In air 5.0 200 72.0 18 Example 2 (0.30) 500 (0.8) Implementation Same as above KOH in nitrogen 5.0 200 73.0 16 Example 3 (0.20) 500 (0.6) Implementation Same as above KOH In air 5.0 200 71.5 17 Example 4 (0.30) 450 (0.6) Implementation Same as above KOH In air 5.0 200 73.0 17 Example 5 (0.20) 550 (0.6) Implementation Same as above KOH In air 10.0 200 75.9 35 Example 6 (0.30) 500 (1.7) Implementation Same as above K_TwoCO_Three 5.0 200 75.0 11 Example 7 (0.20) 500 (0.6) 中─ 1) Alkali metal in alkali compounds
Weight ratio 2) Mixture and baking of alkali compound and carbon material 3) OTP: 5- (o-tolyl) -2-pentene

[0022]

[Table 2] 材料 Carbon material type K compound Firing K compound treatment OTP^{* 3} Reaction Type Atmosphere-Carbon Temperature Yield Number Mixing Ratio Temperature Mixture Volume (° C) (%) (wt Ratio)^{* 1} (℃) (g)^{* 2} Na content (g) 実 施 Implementation MGC AR-Pitch KOH in air 5.0 200 73.5 17 Example 8 400 ° C (0.20) 500 (0.6) under nitrogenHeat treated Implementation AR-Pitch KOH made by MGC In air 5.0 200 72.5 17 Example 9 800 ℃ (0.20) 500 (0.6) under nitrogenHeat treated Implementation PAN synthesis-Pitch KOH in air 5.0 200 72.8 18 Example 10 under nitrogen 510 ° C (0.20) 500 (0.6)Heat treated Implementation Carbongraphite KOH In air 5.0 200 59.7 10 Example 11 (Kanto Chemical) (0.20) 500 (0.6) Activated carbon KOH in air 5.0 200 71.1 12 Example 12 (Kanto Chemical) (0.20) 500 (0.6) ─────────────────────────── ───────── 1) Alkali metal in alkali compounds
Weight ratio 2) Mixture and baking of alkali compound and carbon material 3) OTP: 5- (o-tolyl) -2-pentene

[0023]

[Table 3] 材料 Carbon material type K compound Firing K compound treatment OTP^{* 3} Reaction Type Atmosphere-Carbon Temperature Yield Number Mixing Ratio Temperature Mixture Volume (° C) (%) (wt Ratio)^{* 1} (℃) (g)^{* 2} Na content (g) 比較 Comparison Na-K Example 1 Alloy catalyst 1.6 g use 77.3 9 (Na 6g, K 1.0g) Comparison Alumina KOH in air 5.0 150 82.7 5 Example 2 (0.20) 550 (0.6) Comparison AR-Pitch KOH made by MGC In air 5.0 400 75.0 1 Example 3 Heat treated under nitrogen at 510 ° C (0.20) 500 (0.6) ───────────────────── ─────────────── 1) Alkali metal in alkali compounds
Weight ratio 2) Mixture and baking of alkali compound and carbon material 3) OTP: 5- (o-tolyl) -2-pentene

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-138232 (JP, A) JP-A-59-222427 (JP, A) JP-A-5-97722 (JP, A) JP-A-5-222 112477 (JP, A) JP-A-49-135926 (JP, A) JP-A-51-6930 (JP, A) JP-A-5-148168 (JP, A) JP-A-5-163173 (JP, A) JP-A-62-209027 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 51/44 B01J 23/04 C07C 2/72

Claims (1)

(57) [Claims] 1. A monoalkenyl benzene obtained by alkenylating a side chain of an aromatic hydrocarbon compound having at least one hydrogen atom at the α-position of the side chain with a conjugated diene having 4 or 5 carbon atoms. When producing carbonaceous materials, a carbon material as a catalyst and 0.01 parts by weight of potassium metal per 1 part by weight of the carbon material are used.
To a mixture obtained by calcining ~ 1 part by weight of a potassium compound at 300 to 700 ° C, add metallic sodium under an inert gas, and use a composition obtained by heat-treating at 100 to 350 ° C. A method for producing monoalkenyl benzenes, characterized by the following.